The present invention relates to an intermediate transfer sheet for use in an intermediate transfer type thermal transfer recording method wherein an ink image is first formed on the intermediate transfer sheet by a melt-type thermal transfer method and the ink image on the intermediate transfer sheet is then transferred onto a final image receptor such as a card or a CD-R by thermal transfer using a hot roller, a hot press, etc. In the present specification, the transfer of the ink image on the intermediate transfer sheet onto the final image receptor is sometimes referred to as “retransfer”.
According to the intermediate transfer type thermal transfer recording method, the intermediate transfer sheet is usually composed of a support and a receptive/adhesive layer provided on the support and an ink image is once formed on the receptive/adhesive layer of the intermediate transfer sheet and the ink image on the intermediate transfer sheet is then retransferred onto a final image receptor by thermal transfer using a hot roller, a hot press, etc. Therefore, it is possible to obtain a high-quality image on the final image receptor though depending upon the construction of the receptive/adhesive layer. Also it is possible to improve the adhesion of the ink image onto the final image receptor.
In the prior art, it was frequently carried out to provide a release layer between the support and the receptive/adhesive layer of the intermediate transfer sheet to improve the transferability in the retransferring. The release layer was provided to easily peel the receptive/adhesive layer having the ink image (hereinafter sometimes referred to as “retransfer layer”) from the support, thereby improving the transfer efficiency of the retransfer layer onto the final image receptor. The release layer was composed of mainly a resin having an acrylic skeleton. The transfer efficiency is improved as the release layer is easily peeled from the support. Therefore, it is preferable to minimize the adhesion of the release layer against the support. On the other hand, when the adhesion of the release layer against the support is too weak, there occurs a problem that the retransfer layer is accompanied by transfer failure such as tailing or flash. In order to solve the problem, a polyester resin is usually contained in a release layer, imparting such an adhesion to the release layer that the release layer is appropriately held to the support (see patent document 1).
However, the acrylic resin and the polyester resin which are disclosed in patent document 1 are hardly miscible. Therefore, in the case that the acrylic resin is used as a main component for a release layer, the amount of the polyester resin added is much restricted, resulting in failure to obtain the desired results.
Patent Document 1: JP, A, 11-263079
In view of the foregoing, it is an object of the present invention to provide an intermediate transfer sheet which does not cause transfer failure such as tailing or flash with maintaining satisfactory transfer efficiency of the receptive/adhesive layer having an image (retransfer layer).